With rapid developments of Internet, great convenience has been brought to people and they are more and more dependent on the Internet to carry out various activities, such as network file transmission and online banking which gradually become necessary parts of their lives and work. Since the Internet is a virtual environment, many insecurity factors exist in the Internet. However, Internet activities with data interaction, especially the Internet activities such as Internet banking services and secret file transmission, must be conducted in the Internet, and thus a high requirement for the Internet security is proposed and people start to develop the network information safety technology.
Digital signature technology is a network information safety technology which ensures that the user data that transmitted in the Internet cannot be modified maliciously. The said digital signature technology is an identity authentication technology which is used to transmit instructions and files safely. The digital signature technology processes the user data to be transmitted by a one-way function to obtain an alphanumetric string which is configured to authenticate a resource of the data and to verify whether the data has been modified. The digital signature technology usually calculates a digest value of the data to be transmitted by using a hash algorithm such as MD5 and SHA-1, and transmits an encrypted digest value after encrypting the digest value by an encryption algorithm. Currently, the digital signature technology usually adopts a public-key encryption technology, such as Public Key Cryptography Standards (PKCS), Digital Signature Algorithm, x.509 and Pretty Good Privacy (PGP) of RSA Date Security Corporation. National Institute of Standards and Technology published a digital signature standard in 1994, and thus the public-key encryption technology has been used widely. The digital signature in a digital document is similar to a written signature on a piece of paper and is unforgeable, and a receiver of the document can verify that the document indeed comes from a signer and the signed document has not been modified, such that authenticity and integrity of information in the received document can be ensured. A perfect digital signature technology should satisfy three requirements as follows: first, the signer cannot deny his own signature after the event; second, anyone cannot forge the signature; third, if both parties come into conflict about an authenticity of the signature, the authenticity of the signature can be determined by verifying the signature in front of a just intercessor.
After the data is signed, the security of the data can be improved greatly. However, developments of hacking technology still worry a user, as once a malicious attacker is in control of a computer of the user, he can intercept the data that appears in the computer memory, which causes damage to interests of a legitimate user of the computer. Therefore, people develop a portable and movable electronic signature token which is also known as a USB key. The electronic signature token is a small hardware device having a microprocessor, which establishes a connection with a host through a communication interface of the host. The microprocessor in the small hardware device is generally implemented by a safety chip which achieves functions of generating a key, storing the key and presetting the encryption algorithm by using a built-in security mechanism, such that calculations related to the key are totally performed in an authenticated device, and thus a high safety is provided.
However, the existing electronic signature token having a USB interface only can receive trade information transmitted by a terminal equipment via a USB transmission protocol, and can generate signature data and upload the signature data to the connected terminal equipment via the USB transmission protocol. Once a transmission protocol supported by the terminal equipment is a serial communication protocol or an audio transmission protocol and the terminal equipment sends the data supporting the above serial communication protocol or audio transmission protocol to the existing electronic signature token, the electronic signature token cannot process the data supporting other protocols other than the USB transmission protocol.
In addition, the terminal equipment only can use an interface of its own to transmit data consistent with the transmission protocol supported by the interface. When it is required for the electronic signature token having the USB interface to perform a data transmission with the terminal equipment and the transmission protocol supported by the electronic signature token is different from that supported by the terminal equipment, the terminal equipment cannot perform the data transmission with the electronic signature token due to limitations of the interface of the terminal equipment and the transmission protocol supported by the terminal equipment.
For example, a serial device (such as a POS machine) only has a serial interface, and when it is required for the electronic signature token having the USB interface to perform the data transmission with the serial device, the serial device cannot perform the data transmission with the electronic signature token, as the serial device does not have the USB interface and does not support the data transmitted via the USB transmission protocol. Thus, the use of the electronic signature token is limited.
Although a smartphone supports the USB transmission protocol, the smartphone only can be used as a slave USB device, and the electronic signature token having the USB interface also is the slave USB device, and thus the smartphone cannot perform a data interaction with the electronic signature token via the USB transmission protocol. If the smartphone intends to perform the data interaction with the electronic signature token having the USB interface via an audio transmission protocol, the electronic signature token having the USB interface cannot perform the data interaction with the smartphone via the USB interface, as the electronic signature token having the USB interface does not support other data transmission protocol types other than the USB transmission protocol.